**Core Concept**
Tinea capitis is a fungal infection of the scalp, caused by dermatophytes such as Trichophyton, Microsporum, and Epidermophyton species. Effective treatment requires antifungal agents that can penetrate the hair shaft to reach the fungal infection site.

**Why the Correct Answer is Right**
Oral griseofulvin therapy is the most appropriate line of treatment for tinea capitis. Griseofulvin is a fungistatic antifungal agent that binds to keratin, the primary protein in hair, nails, and skin. This binding action inhibits fungal growth and proliferation. Griseofulvin is lipophilic, allowing it to penetrate the hair shaft and reach the site of infection. The recommended duration of treatment is usually 6-8 weeks to ensure complete clearance of the fungal infection.

**Why Each Wrong Option is Incorrect**
**Option B:** Topical griseofulvin therapy is not effective for tinea capitis because griseofulvin does not penetrate the hair shaft well when applied topically, making it difficult to reach the site of infection.

**Option C:** Shaving of the scalp is not a recommended treatment for tinea capitis as it does not address the underlying fungal infection and may lead to further spread of the disease.

**Option D:** Selenium sulphide shampoo is an adjunctive treatment for tinea capitis, used to reduce the fungal load on the scalp and prevent further spread of the infection. However, it is not a standalone treatment and should be used in conjunction with antifungal agents like griseofulvin.

**Clinical Pearl / High-Yield Fact**
It is essential to note that oral griseofulvin therapy may have side effects such as gastrointestinal upset, headache, and skin rash. Regular monitoring of liver function and complete blood counts is recommended during treatment.

**✓ Correct Answer: A. Oral griseofulvin therapy**